#! perl -slw
use strict;

package fred;

sub new {
    my $class = shift;
   return bless { @_ }, $class;
}

sub method {
    my $self = shift;
    return keys %{ $self };
}

return 1 if caller;
package main;

our $MAX //= 10;
print 'Max: ', $MAX;

my $o = fred->new( 'a' .. 'z' );

print for $o->method;

__END__
C:\test>perl -s fred.pm -MAX=123
Max: 123
w
e
a
m
s
y
u
c
k
q
g
i
o